Argon protection structure for reducing atmosphere of external refining ladle cover
By using the outer refining cover for the furnace outside the LF furnace, the atmosphere argon protection structure is reduced, and argon is used to form a positive pressure swirl, which solves the problem of insufficient protection atmosphere in the ladle and ensures the quality of smelting.
Patent Information
- Application Number
- CN202510431985.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-06-27
AI Technical Summary
During the refining process outside the LF furnace, the protective atmosphere inside the ladle is insufficient, causing external air to enter the ladle, affecting the quality of smelting.
A refining cover reducing atmosphere argon gas protection structure outside the furnace is adopted, and argon gas is introduced into the ladle through the furnace cover, forming a continuous positive pressure swirl in the protection area to prevent the entry of external air.
Ensure that the ladle is in a slightly positive pressure state, avoid external air entering, stabilize the protection atmosphere, and improve the smelting effect.
Smart Images
Figure CN120210453A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of metal smelting, specifically to the argon blowing technology in metal smelting, and particularly to an argon protection structure with a reducing atmosphere for the ladle cover in secondary refining. Background Art
[0002] Currently, in oil extraction and oil and gas transportation, the demand for ultra-low sulfur acid-resistant steel is becoming increasingly significant. It requires S≤0.003%, with the target being 0.001%. Therefore, in the process of secondary refining in the LF furnace, in addition to deoxidation and slag system control, the protection of the reducing atmosphere is also equally important.
[0003] The traditional smelting method is to reduce the height of the LF furnace cover. However, due to slag accumulation at the ladle edge, a relatively large gap needs to be reserved between the furnace cover and the ladle to prevent the graphite electrode from breaking during the smelting process of the LF furnace cover and to avoid slag accumulation from blocking the gap between the furnace cover and the ladle.
[0004] In the field of secondary refining technology of the LF furnace, since the furnace cover and the ladle do not contact, during the smelting process, convection will form between the inside and outside air of the ladle at the gap between the furnace cover and the ladle. Even if there is a sufficient positive pressure protection atmosphere inside the ladle, with the air convection, the external air will still enter the ladle, thereby affecting the quality of molten iron smelting. Summary of the Invention
[0005] The technical problem to be solved by the present invention is: to solve the technical problem of insufficient protection atmosphere inside the ladle during the secondary refining process of the LF furnace in the prior art. The present invention provides an argon protection structure with a reducing atmosphere for the ladle cover in secondary refining, which can continuously form a positive pressure protection atmosphere inside the ladle, prevent external air from entering the ladle through the gap between the furnace cover and the ladle, and ensure the smelting effect.
[0006] An argon protection structure with a reducing atmosphere for the ladle cover in secondary refining of the present invention includes a protective furnace cover. The protective furnace cover is arranged above the ladle. An electrode extending into the ladle is provided through the protective furnace cover. A protective area communicating with the external air is formed between the protective furnace cover and the ladle. The protective furnace cover has a protective gas passage communicating with the protective area. The argon gas flowing into the protective area through the protective gas passage forms a continuous positive pressure swirling protective atmosphere in the protective area, thereby blocking the entry of external air into the protective area.
[0007] For the argon protection structure with a reducing atmosphere for the ladle cover in secondary refining of the present invention, argon gas is introduced through the protective furnace cover to form a continuous positive pressure swirl in the protective area, making the protective area in a slightly positive pressure state relative to the external air, preventing external air from entering the ladle through the gap between the protective furnace cover and the ladle and contacting the molten steel, and ensuring the smelting effect of the molten steel.
[0008] Further, in order to form a positive-pressure swirling flow inside the protective furnace cover, reducing argon gas flowing towards the protective furnace cover is formed by the ladle. After the argon gas flowing into the protection area impacts the ladle, it rises following the reducing argon gas and impacts the protective furnace cover, thereby forming a continuous positive-pressure swirling flow.
[0009] Further, in order to ensure that the reducing argon gas can flow upward, there is a gap between the protective furnace cover and the electrode, and the protective atmosphere flows out of the protective furnace cover through this gap.
[0010] Further, in order to better form a positive-pressure swirling flow, the included angle between the argon gas flowing into the protection area and the horizontal direction is 45° - 65°.
[0011] Further, in order to control the flow direction of the argon gas entering the protection area, a plurality of Laval nozzles are provided on the protective gas channel. The Laval nozzle includes a reduced-diameter section communicating with the protective gas channel and an arc section facing the protection area. The argon gas forms an arc-shaped air flow flowing into the protection area via the reduced-diameter section and the arc section.
[0012] Further, in order to direct the argon gas into the nozzle, the reduced-diameter section is inclined with respect to the horizontal direction.
[0013] Further, in order to ensure the formation of a uniformly distributed positive-pressure swirling flow in the protection area, the protective gas channel is arranged along the circumferential direction of the protective furnace cover, and the Laval nozzles are arranged at equal intervals around the circumferential direction of the protective furnace cover.
[0014] Further, in order to prevent the pressure in the protection area from being too high, the protective furnace cover is arranged with a gap from the ladle rim and forms a bent air flow channel. The argon gas in the protection area flows into the external air through the air flow channel.
[0015] Further, in order to prevent slag accumulation from blocking the gap between the furnace cover and the ladle, the protective furnace cover includes a cover body and a cover rim. The cover body is arranged at an interval from the ladle rim. The protection area is a cavity between the inner side of the ladle and the bottom of the cover body. The cover rim is located outside the ladle rim and is arranged at a distance from the ladle.
[0016] Further, in order to prevent the protective atmosphere in the protection area from flowing too quickly into the external air, the gap between the cover body and the ladle rim is 100 mm - 150 mm.
[0017] Compared with the prior art, the beneficial effects of the present invention are:
[0018] 1. For the argon gas protection structure with a reducing atmosphere for the ladle cover in the secondary refining outside the furnace of the present invention, argon gas is introduced into the ladle through the protective furnace cover, and a positive-pressure swirling flow is formed between the protective furnace cover and the ladle, making the ladle in a slightly positive-pressure state, preventing external air from entering the ladle through the gap between the protective furnace cover and the ladle, and ensuring the smelting effect.
[0019] 2. The argon protection structure with reducing atmosphere for the ladle cover in the secondary refining of the present invention forms a continuous positive-pressure swirling flow in the protection area under the combined influence of molten steel slag, the protection ladle cover, and reducing argon gas, maintaining a stable positive-pressure protection atmosphere in the ladle to prevent the molten iron from contacting the external air and being oxidized.
[0020] 3. The argon protection structure with reducing atmosphere for the ladle cover in the secondary refining of the present invention has the protection ladle cover and the ladle arranged at intervals to control the flow rate of the air flow in the protection area flowing towards the external air, avoiding insufficient positive-pressure atmosphere inside the protection area and affecting the protection effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The present invention will be further described below in conjunction with the drawings and embodiments.
[0022] Figure 1 is a schematic structural diagram of the argon protection structure with reducing atmosphere for the ladle cover in the secondary refining of the present invention;
[0023] Figure 2 is a top view of the argon protection structure with reducing atmosphere for the ladle cover in the secondary refining;
[0024] In the figure: 1. Protection ladle cover, 11. Cover body, 12. Cover edge, 13. Protection gas channel, 14. Laval nozzle, 15. Air flow channel, 2. Ladle, 21. Protection area, 3. Electrode. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0025] The present invention will now be described in further detail in conjunction with the drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present invention in a schematic manner, so they only show the components related to the present invention.
[0026] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.
[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0028] For example Figure 1 , an argon protection structure with a reducing atmosphere for the ladle cover in secondary steelmaking, includes a protective ladle cover 1, the protective ladle cover 1 is arranged above the ladle 2, and an electrode 3 extending into the ladle 2 is penetrated through the protective ladle cover 1. The protective ladle cover 1 includes a cover body 11 and a cover edge 12, the cover body 11 is arranged at an interval from the rim of the ladle 2, the cover edge 12 is located outside the rim of the ladle 2 and is arranged at a distance from the ladle 2. The bottom layer of the ladle 2 is molten iron, and molten steel slag is above the molten iron.
[0029] A protective area 21 communicating with the external air is formed between the protective ladle cover 1 and the ladle 2, and the protective area 21 is a cavity between the inner side of the ladle 2 and the bottom of the cover body 11. The protective ladle cover 1 has a protective gas passage 13 communicating with the protective area 21, and the argon flowing into the protective area 21 through the protective gas passage 13 forms a continuous positive-pressure swirling flow in the protective area 21, thereby blocking the entry of external air into the protective area 21. Argon is blown into the protective area 21 through the protective gas passage 13. Since the flow direction of argon will change when it impacts the molten steel slag in the ladle 2, a positive-pressure swirling flow will be formed in the ladle 2. The positive-pressure swirling flow can be evenly distributed in the space of the protective area 21. Therefore, the air pressures at various places inside the entire protective area 21 are very close and are all in a slightly positive pressure state. Since the air pressure of the external air is lower than that of the protective area 21, the argon in the protective area 21 will flow into the external air from the gap between the protective ladle cover 1 and the ladle 2. Under the action of the continuously blown argon and the pressure difference, external air cannot flow into the interior of the ladle 2 from the gap between the ladle cover and the ladle 2. Therefore, a continuous positive-pressure swirling flow always exists in the protective area 21, and the direction of the positive-pressure swirling flow is as shown by the arrow a in Figure 1 .
[0030] Specifically, the ladle 2 forms reducing argon flowing towards the protective ladle cover 1, and the reducing argon is carbon monoxide and carbon dioxide. The flow direction of the reducing argon is as shown in Figure 1As shown by arrow b, after the argon gas flowing into the protection area 21 impacts the ladle 2, it rises following the reducing argon gas and impacts the protection furnace cover 1, thus forming a continuous positive-pressure swirling flow. Since there is molten iron in the ladle 2 and the surface of the molten iron is slag, the argon gas blown into the protection area 21 will flow downward and impact the slag, causing the flow direction of the argon gas to change. Under the action of the reducing argon gas generated in the molten steel, the argon gas will rise following the reducing argon gas, and the argon gas collides with the cover body 11, and the flow direction of the argon gas changes again, thereby forming a stable positive-pressure swirling flow protection atmosphere in the protection area 21. The positive-pressure swirling flow is as Figure 1 shown by the arrow in
[0031] Preferably, there is a gap between the protection furnace cover 1 and the electrode, and the protection atmosphere flows out of the protection furnace cover 1 through this gap. This can ensure that the reducing argon gas flows stably upward, can better drive the argon gas to flow upward, and then form a stable positive-pressure swirling flow protection atmosphere. The protection atmosphere can prevent external air from entering the ladle and prevent the molten iron in the ladle from contacting the air and oxidizing.
[0032] Preferably, the included angle between the argon gas flowing into the protection area 21 and the horizontal direction is 45° - 65°. The argon gas blown in from this angle is more likely to form a stable positive-pressure swirling flow in the protection area 21, so that the air flow can fill the protection area 21 more evenly.
[0033] Preferably, a plurality of Laval nozzles 14 are provided on the protection gas channel 13. Preferably, 4 Laval nozzles are used in this embodiment. The Laval nozzle 14 includes a reduced-diameter section communicating with the protection gas channel 13 and an arc section facing the protection area 21. Specifically, the radian of the arc section is R100 - 200. The argon gas forms an arc-shaped air flow flowing into the protection area 21 through the reduced-diameter section and the arc section. The reduced-diameter section is inclined with respect to the horizontal direction. The argon gas changes the air flow direction in the Laval nozzle 14, and the flow rate of the argon gas passing through the Laval nozzle 14 increases, and it can be blown more quickly into the interior of the ladle 2, making the positive-pressure air swirl flow faster and more stable.
[0034] Preferably, the protection gas channel 13 is arranged along the circumferential direction of the protection furnace cover 1, and the Laval nozzles 14 are arranged at equal intervals around the circumferential direction of the protection furnace cover 1. In this way, the positive-pressure swirling flow can be evenly distributed in the circumferential direction of the protection area 21, ensuring uniform air flow inside the protection area 21.
[0035] The protection furnace cover 1 is provided with a gap with the rim of the ladle 2, and a bent air flow channel 15 is formed. The argon gas in the protection area 21 flows to the external air through the air flow channel 15, and the air flow direction is as Figure 1As shown by arrow c. The gap between the cover body 11 and the ladle rim of the ladle 2 is 100 mm - 150 mm. Since the positive selected air flow flows through the gap to the external air, in this case, it is not easy to form slag accumulation between the cover body 11 and the ladle 2. At the same time, in order to prevent the argon gas in the protection area 21 from flowing too quickly to the external air, the bent air flow channel 15 can slow down the argon gas flow rate and flow volume. At the same time, the bent air flow channel 15 is still in a slightly positive pressure state relative to the external air, and the external air will not enter the ladle through the bent air flow channel 15, and the consumption of argon gas is reduced.
[0036] In summary, the argon gas protection structure with a reducing atmosphere for the ladle cover of the present invention can continuously form a positive pressure protection atmosphere in the ladle, prevent external air from entering the ladle through the gap between the ladle cover and the ladle, and ensure the smelting effect.
[0037] The above is based on the ideal embodiments of the present invention as an inspiration. Through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.
Claims
1. An argon protection structure for reducing atmosphere of an off-furnace refining ladle cover, comprising a protective furnace cover (1), wherein the protective furnace cover (1) is arranged above a ladle (2) at a distance, and wherein the protective furnace cover (1) is provided with an electrode (3) extending into the ladle (2), wherein the protective furnace cover (1) is provided with an electrode (3) extending into the ladle (2), wherein the protective furnace cover (1) is characterized in that: A protection area (21) connected to the outside air is formed between the protection furnace cover (1) and the ladle (2), and the protection furnace cover (1) has a protection gas channel (13) connected to the protection area (21). Argon gas flowing into the protection area (21) through the protection gas channel (13) forms a continuous positive pressure swirl protection atmosphere in the protection area (21), thereby blocking the outside air from entering the protection area (21).
2. The protective furnace cover according to claim 1, characterized in that: The ladle (2) forms reducing argon gas that flows toward the protective furnace cover (1). After the argon gas that flows into the protective area (21) hits the ladle (2), it rises with the reducing argon gas and hits the protective furnace cover (1), thereby forming a continuous positive pressure swirl protective atmosphere.
3. The protective furnace cover according to claim 2, characterized in that: There is a gap between the protective furnace cover (1) and the electrode (3), and the protective atmosphere flows out of the protective furnace cover (1) through the gap.
4. The protective furnace cover according to claim 3, characterized in that: The angle between the argon gas flowing into the protection area (21) and the horizontal direction is 45°-65°.
5. The protective furnace cover according to claim 1, characterized in that: The protective gas channel (13) is provided with a plurality of Laval nozzles (14), wherein the Laval nozzles (14) comprise a reduced diameter section connected to the protective gas channel (13) and an arc section facing the protective area (21), and the argon gas forms an arc-shaped airflow flowing into the protective area (21) via the reduced diameter section and the arc section.
6. The protective furnace cover according to claim 5, characterized in that: The reduced diameter section is arranged to be inclined with respect to the horizontal direction.
7. The protective furnace cover according to claim 1, characterized in that: The protective gas channel (13) is arranged along the circumferential direction of the protective furnace cover (1), and the Laval nozzles (14) are arranged at equal intervals around the circumferential direction of the protective furnace cover (1).
8. The protective furnace cover according to claim 1, characterized in that: The protective furnace cover (1) and the ladle edge of the steel ladle (2) are provided with a gap, and a bent airflow channel (15) is formed, and the argon gas in the protection area (21) flows into the external air through the airflow channel (15).
9. The protective furnace cover according to claim 8, characterized in that: The protective furnace cover (1) comprises a cover body (11) and a cover edge (12); the cover body (11) is spaced apart from the edge of the ladle (2); the protection area (21) is a cavity between the inner side of the ladle (2) and the bottom of the cover body (11); the cover edge (12) is located outside the edge of the ladle (2) and is spaced apart from the ladle (2).
10. The protective furnace cover according to claim 9, characterized in that: The gap between the cover (11) and the edge of the ladle (2) is 100 mm to 150 mm.